Preparation And Study Of Sol Vitrified Diamond Stacking Abrasive By Centrifugal Spray Drying

As a new type of agglomerated abrasive,stacked abrasives has a broad application prospect in the field of precision grinding processing,which participate in grinding process with multiple layers of abrasives,improving the grinding efficiency and the surface quality significantly,and solving the problems effectively of the ordinary single abrasives,such as low efficiency,poor self-sharpening and machining surface quality in machining process.In this paper,the vitrified bonds and corresponding vitrified diamond composites are prepared by sol-gel and melting method.The effects of the preparation methods on the structural and properties of vitrified bonds are systematically compared,and the corresponding mechanism has been explained.Furthermore,the vitrified diamond stacked abrasives are prepared by centrifugal spray drying method.And the influence of atomization parameters on the characteristics of stacked abrasive are systematic discussed.The grinding performance of the obtained stacked abrasive is compared with those of 3M and a domestic company.Following conclusions are obtained:1)The glass network of the vitrified bond prepared by sol-gel method contained more[Al O₄],and its maximum bending strength was 137 MPa,which was 31.73%higher than that prepared by melting method(104 MPa).As the temperature rose,the thermal expansion coefficient of sol-gel vitrified bond increased first and then decreased,acquiring a maximum of 5.75×10^-6?^-1 at 720°C,which was far lower than that of melting vitrified bond(7.01×10^-6?^-1),matching better with diamond.And the maximum bending strength of sol-gel vitrified diamond composites was 106 MPa,which was 24.7%higher than that of melting vitrified diamond composites(85 MPa).2)Vitrified diamond stacked abrasive was prepared by centrifugal spray drying method with the sol-gel vitrified bond as binder and the 3000#diamond powder as abrasive particles.The optimal atomization parameters were as following:the slurry solid content was 31wt.%,the centrifugal speed was 21000 rpm,the feed speed was150 ml/min at the drying temperature of 80?.Under these conditions,the flow performance of stacked abrasives obtained was optimal with the value of 23.9 s/50g,the recovery rate under 100 meshes was 81.84%,and the d₁₀,d₅₀,and d₉₀ of particles were 35.74?m,52.49?m,and 81.23?m,respectively.The apparent density was 1.281g/cm³.3)Compared with the abrasive pad produced by a domestic enterprise,the abrasive pad prepared by the stacked abrasive obtained by centrifugal spray drying method had a cutting force increased by 41.67%,the workpiece scratch rate decreased by 8%,and the workpiece surface roughness reduced by 10.6%.And compared with the 3M abrasive pad,the abrasive pad prepared by centrifugal spray drying had a higher cutting force(7 s/C),but the scratch rate and the workpiece surface roughness were higher.